In Part 1, we discussed the behaviors that had to change for wolves (Canis lupus) to evolve into dogs (Canis lupus familliaris). Lone wolves tend to be shy, but in packs they can be deadly predators, and neither of these behavior extremes would be useful or welcome in human communities. But as wolves self-domesticated, wanting access to humans’ dependable food source, the human/proto-dog relationship gradually became one of mutuality with proto-dogs barking warnings, guarding settlements and flocks, participating with humans in hunting expeditions, and ingratiating themselves into human relationships. None of this occurred overnight, but because wolves instinctively understand social hierarchy and both humans and wolves were finding the relationship mutually beneficial, the evolution from wolf to proto-dog to dog was possible and slowly began to happen.

So, what do human beings love to do? We love to tinker with things.  We like to make things better to more precisely suit our needs. Natural selection is an extremely slow, centuries-long process that only occurs when certain traits give members of the same species a physical advantage, resulting in higher reproduction rates.  In wolves, that fortuitous trait was their willingness to tolerate humans nearby while feeding at human dump sites. This “friendly trait” got passed on to wolf offspring, causing a gradual evolution of the species toward consistently expressing that trait. While that certainly facilitated the start of human-wolf interactions, natural selection is an excruciatingly slow process. And once humans realized that evolving wolves might be useful, the desire to speed up natural selection was inevitable. Early humans noticed which traits were useful in proto-dogs and began controlling breeding to replicate and heighten those traits. Faster proto-dogs would be used for hunting and be bred to other fast dogs to increase that skill; calmer proto-dogs would be bred together to produce stable working and guardian dogs; smaller-sized proto-dogs would produce more functional companions if calm and friendly, or varmint hunters if more aggressive. These controlled breeding practices led to what is called artificial selection, humans tinkering with natural processes.

For many centuries, through artificial selection, humans bred a few basic dogs for a few basic functions: guard dogs, war dogs, companion dogs, hunting dogs, working dogs, etc. Until the beginning of the 19th century, when suddenly, new scientific theories, a higher incidence of a leisured class, especially in Europe, and mankind’s natural curiosity all created a perfect storm of interest in dog breeding. At that time, our tinkering became much more focused and serious as the concept of a dog with a precise function and look became popular, not just for kings and nobility, but for the general population.

As evolutionary scientists now view canine history:

• 40,000 – 30,000 years ago,​​wolves and wolf-like ancestors
• 30,000 – 20,000 years ago,​​wolves developed into proto-dogs​
• 20,000 – 11,000 years ago, the domestication of proto-dogs into dogs
• 11,000 years ago – 1800 AD​specialization of dog breeds through ​​​​​​artificial selection​
• 1800 AD – present day​​hybridization of dog breeds

Artificial selection basically means human-controlled selection of breeding to increase the dominance of certain desirable traits. This focused breeding continued for many years, with humans choosing their dogs’ mates to produce sturdier working dogs, smaller lap dogs, hunting dogs with keener eyesight or better noses, etc. But during the 1800’s, Europe was entering an era of great scientific exploration fueled by the British naturalist Charles Darwin’s theory of evolution and the biological studies of the Austrian monk, Gregor Mendel’s genetic research. These and similar scientific advances dramatically influenced the desire to create better agriculture and domestic animals through the use of highly selective breeding, termed hybridization.

Hybridization in dog breeding happens when people intentionally cross different dog breeds, hoping to combine desirable characteristics in offspring, leading to new breeds. Let’s look at the Bullmastiff as a typical example of canine hybridization.

In the early 1800’s the great estates in England were being continuously attacked by poachers who were stealing the landowner’s wild game. For this article, I will put aside sociological factors and stick with dog breeding. Some of the landowners were using Mastiffs to guard their property, and others were using the Old English Bulldog, but neither breed was doing a satisfactory job.  The Mastiffs were too slow, and if they did manage to catch a wildlife thief, they usually killed him.  The Old English Bulldog was more agile and tenacious but also fierce and a killer. Evidently, at that time, the gentry wanted poachers caught and turned over to the law instead of mutilated or killed on their property, so they set out to develop a new breed that would suit their purpose. Through hybridization of the two breeds, and most likely a little bit of Bloodhound to improve tracking ability, they eventually produced the Bullmastiff, or as it was called at the time, the Gamekeeper’s Night Dog.

The dog these breeders developed was around 135 pounds (smaller than the Mastiff but larger than the Bulldog), very strong (Mastiff) but able to sprint for short distances (Bulldog), had a very good nose (Bloodhound) and was docile enough (probably some unknown less aggressive breeds that have been lost to time) to live with the gamekeeper and his familybut threatening enough to take down a poacher and hold him fast without mauling him until the gamekeeper could cuff the thief. The breed was purposely bred to have excellent bite control, and the correct proportions of the dogs were to be 60% Mastiff and 40% Bulldog.

Hybridization happens quickly. From their first crosses in the early 1800’s, Bullmastiffs were recognized as a distinct new breed in 1924 by the American Kennel Club. In just over 100 years, humans had tinkered with canine genetics and created a wholly new form of dog to fill a very specific human need.

We have explored how over long periods of time wolf behavior and wolf appearance have evolved into dog behavior and dog appearance, and how humans played and continue to play a vital role in the process. Next month we will discuss more about the physical and biological differences and similarities between these two interconnected species, and how some of our modern practices may be harming our best friends.​​